1. Field of the Invention
The present invention relates to a terminal box constituting an output section of a solar battery module constituting a solar power generation system.
2. Description of the Related Art
In a terminal box constituting an output section of a solar battery module, a circuit constituting section constituted by a terminal board, a bypass diode, an output cable, and the like is housed within a box body having one open side. The circuit constituting section is buried by filling a potting material, and the opening side of the box body is closed with a cover (for example, see the Publication No. 2001-168368 of unexamined application, illustrated in FIG. 1).
In the above-described conventional terminal box for solar battery module, the circuit constituting section is potted with a silicon resin excellent in thermal conductivity. Thus, the heat generated from the bypass diode and the like is dissipated through the potting material. The potting material fills the terminal box, covering the surface of a charging section and the inner walls of the box body of the terminal box so as not to leave any gap. Although the potting material serves to prevent the breaking or breakage of the bypass diode owing to its heat dissipation effects, the penetration of water or moisture to the charging section, and the adhesion of any dust, the potting material is sometimes thermally deformed due to heat generated from the circuit constituting section. The thermal deformation of the potting material leads to deformation of the box body or the cover, whereby the capability of the potting material of preventing water or moisture from entering the charging section may sometimes be impaired. In order to prevent such a problem, the following means have been conventionally employed. A plurality of bypass diodes are connected in series and in parallel so as to reduce the amount of heat generation by each bypass diode. Alternatively, the surface area or the volume of the potting material or the terminal board is increased so as to enhance the heat dissipation efficiency. Further alternatively, the area of a solar battery cell is reduced to decrease the amount of heat generated by the bypass diode. However, the use of these means disadvantageously induces an increase in size of the terminal box, an increase in fabrication cost, or a drop in mass productivity.